1. Field of the Invention
The invention relates to an arrangement for voltage measurement in a gas-insulated switchgear having an isolated-phase bus, a current-carrying bus with a given external radius R.sub.1 being arranged coaxially in a cylindrical enclosure with a given external radius R.sub.2.
2. Discussion of Background
Conventional voltage and current measurement in gas-insulated switchgears, abbreviated to GIS installations, is normally done using inductive measuring transducers. A review of conventional metrology is given in the publication "Grundkurs der Messtechnik I" (Basic Metrology Course I), L. Merz, R. Oldenbourg Verlag, Munich - Vienna, 1968, pages 155 to 160.
In such applications, conventional sensors are very voluminous, something which is bound up not least with the necessary, complicated electrical isolation of the measuring transducer of the installation.
A large number of optical sensors for measuring electrical quantities such as current and voltage have recently been developed. Optical fiber sensors are particularly user-friendly in this regard. The following publications are important in this connection:
For voltage measurement:
EP 0,316,619 A1, K. Bohnert, J. Nehring: a selected directional component of an electric field is measured with the aid of the inverse piezoelectric effect.
For current measurement:
CH 659,329 A5, R. Dandliker: the Faraday effect caused by a current in a glass fiber is detected with the aid of a Sagnac interferometer.
Swiss Patent Application 3246/88-9, F. Maystre, A. Bertholds: the current sensor is a helical fiber, which goes round the current exactly once.
"Magneto-optical current transformer", A. Papp, H. Harms, Appl. Optics 19 (1980), page 3729: optical current sensor in accordance with the principle of the polarimetric method.
"Magneto-optic current sensing with birefringent fibers", S. C. Rashleigh, R. Ulrich, Appl. Phys. Lett. 34 (1979), page 768.
"Development of low- and high-birefringence optical fibers", D. A. Payne et al., IEEE J. of Quantum Electron. QE-18 (1982), page 477.
"The rotation of the polarization in low birefringence monomode optical fibers due to geometrical effects", J. N. Ross, Optical and Quantum Electronics 16 (1984), pages 455-461.
Nonconventional optical sensors offer a compact design and an inherent electrical isolation. In addition, they are largely insensitive to disturbing electrical and magnetic influences. For this reason, they are predestined for application in GIS installations. However, it has not so far been clear how optical sensors are advantageously to be integrated into a GIS installation.